Air cooling system for vehicles



Aprifi 28, 1936. J, F RE H zmww AIR COOLING SYSTEM FOR VEHICLES OriginalFiled Jul 25, 1952 Patented Apr. 28, 1936 UNITED STATES PATENT OFFICEAIR COOLING SYSTEM FOR VEHICLES Joseph F. Frese, Baltimore, Md.,assignor to Monitor Controller Company, Baltimore,, Md., a corporationof Maryland '7 Claims.

This application is a division of my application Serial Number 624,594,filed July 25, 1932, patented November 27, 1934, No. 1,981,859.

The invention relates to a n/air conditioning system suitable for use onrailway passenger cars for keeping the air in the car at a desiredtemperature. In such a system, power is required to operate thecompressor of a refrigerating apparatus and I employ as a driving meansfor the compressor an internal combustion engine, with means controlledby a thermostat switch for starting the engine and compressor when thetemperature of the air in the car rises to a predetermined degree, andfor stopping the engine and compressor when the temperature of the airis lowered to a predetermined degree. i

As an internal combustion engine must be cranked to start it, and alsochoked, if it happens to be cool, and as it may not start until it hasbeen cranked and choked several times, I provide means for automaticallycranking the engine intermittently for predetermined time periods andfor closing the choke valve during a part of each period. When theengine starts, a switch controlled by the operation of the engine opensand circuits controlling the starting and choking devices are therebyopened and these devices become inoperative. If the engine does notstart after a predetermined number of cranking and choking operations, acircuit breaker is automatically opened and this disables a circuitwhich controls the ignition circuit of the engine and the circuits ofthe starting and choking devices. It may be that, if the engine does notstart after several cranking and choking operations, there is somethingwrong with the system,

requiring ersonal attention, such as exhaustion of the fuel supply andtherefore the circuit breaking device is provided for disabling thestarting devices after a predetermined number of these operations. Thecircuit breaker must be manually reset before the apparatus can be againplaced under automatic control and this insures individual attention.

In this air conditioning system a fan motor is employed to circulate theair in the car or room past the refrigerating coils. It is essential to.haveing fan motor is in operation, and whereby interruption of thecircuit of this motor will cause stoppage of the gas engine andcompressor if these happen to be working at the time.

I provide also an electric motor for circulating a cooling medium aroundthe condensing coil at the compression side of the compressor, shownherein diagrammatically as a fan motor, although it may be a motorconnected to a pump where liquid is used for causing condensation of thefluid used for refrigeration. This motor, used for cooling, must be inoperation while the compressor is working.

To place the system in operative condition, the air circulating fanmotor must first be started. The starter for this motor, when closed,makes up a circuit to the magnet of a normally open relay switch, whichcircuit is, however, normally open at a push button switch. Upon theclosure of this push button switch, the relay is energized and connectsa starter for the cooling motor to one side of the supply circuit. Themain contactor magnet of this starter, connected to one side of the lineby said relay, is connected to the other side of the line through asafety circuit which includes a thermostat switch. The starter. lastreferred'to cannot operate except when the thermostat switch is closed.When closed, the starter completes the circuit to the cooling motor andalso makes up the circuits of the engine controlling devices previouslyreferred to, and the engine then operates the refrigerating apparatus.When the temperature in the room rises sufficiently to cause thethermostat switch to open, the circuit through the magnet oi the maincontactor of the starter is opened and the starter opens the circuit ofthe cooling motor and the interlocking connections to the enginecontrolling devices.

In the accompanying drawing, the invention is illustrateddiagrammatically.

Referring to the drawing, A represents the compressor of a refrigeratingsystem; B indicates an internal combustion engine for operating thecompressor, and C indicates an electric starting motor for the engine.The circulating system for the refrigerant is indicated by a pipe Ileading from the compression side of the compressor to a condensing coil2, wherein the fluid is cooled by air or other cooling fluid circulatedaround the coil by an electricmotor D, a pipe 3 leading through anexpansion valve 4 to a refrigerating coil 5, and a pipe 6 leading fromthe latter coil to the intake side of the compressor. The coil 2, whichgives off heat generated by compression of the refrigerating fluid, willbe placed outside of the room which is to be cooled, or in a compartmentby itself. In the diagram, the dotted line 1 indicates such acompartment. The refrigerating coil 6, which is cooled by the expandedrefrigerant and absorbs heat from the air, is placed within, or incommunication with, the room to be cooled, and a fan motor E is providedfor circulating the air of the room around and between the convolutionsor the coil.

A relay F controls the ignition circuit of the engine; a relay Mcontrols the circuit of the starting motor, and a magnet H controls theactuation of the choke valve of the engine. A motor driven timingmechanism J, controls the circuits of the relay Mand magnet H and alsothe circuit of a tripping device K which is adapted to open a safetycircuit in case the gas engine does not start after a predeterminednumber of cranking'and choking operations. The opening of this circuitdisables the circuits of the various devices which control the startingand running of the gas engine and the automatic mechanism will notoperate untilthe circuit is closed by hand. This. safety circuitincludes a thermostat switch .T which, by changing temperature in theroom, operates to close or open the circuit and thereby control thestarting and stopping of the engine, when the tripping switch is closed.

In the diagram, L and L' indicate the supply wires leading from asuitable current source, subh as the battery which furnishes current forlighting on railway passenger cars and which is usually charged by adynamo driven from the axle of the car. It is essentialthat the fanmotor E, for the coil 5, shall be in operation at all times while thecompressor is operating, and to insure this, the circuits and interlocksare so arranged that this motor must be started before any of the othermechanisms can operate. The motor E may be started by momentarilydepressing a normally open push button switch marked Fan and it can bestopped by momentarily depressing a normally closed push button switchmarked Stop. The circuits of the motor are controlled by a starter Gcomprising a main contactor g and an auxiliary contactor a. The armaturecircuit 0! the motor, shown in heavy lines, extends from supply wire Lthrough conductor 8 to the normally open main contactor y, thencethrough arm 9 of the contactor to conductor [0, which is connected toarm ll of contactor g and to the coil of masnet |2, thence throughconductor l3, starting resistance l4 and series coil ii to the armatureofmotor E and thence through conductor It to the supply wire L. Theshunt field circuit of the motor extends from conductor it throughconductor l1 and the fleldwinding I8 to the supply wire L.

The normallyopen push button switch marked Fan" is in a circuit whichextends from the supply wire L by conductor I 8 to the magnet of thecontactor a, thence through conductor 21, resistance 22 and normallyclosed stop push button to the supply wire L. By momentarily depressingthe fan push button, the magnet 20 is energized and the contactor arm 9closes the armature and field circuits and the motor starts. When thearm 8 closes, it establishes a holding circuit 20 for the magnet andcompletes a circuit from supply wire L and conductor 8 through conductor23 and shunt magnet 24 of contactor g, to conductor 2| and the supplywire L. The contactor arm I i is centrally pivoted and the magnet 24tends to rock it to closed position, but the m net I2, which is inseries with the motor armature, holds the contactor in open positionuntil the starting current of the motor falls to a predetermined value,when the shunt magnet overpowers the series magnet and the contactor armis rocked to closed position. The contactor arm is connected to the partID of the armature circuit, as shown, and when the arm closes, itestablishes a shunt circuit 25 around the starting resistance l4,thereby cutting out said resistance. The fan motor E now operates toblow air around the coil 5 and will continue to operate until the stoppush button is depressed to break the circuit through the magnet 20.When this occurs, the contactor Q will open and break the circuitthrough the field and armature of the motor as well as through themagnets of the contactor a and the contact arm of the latter will moveto open position.

When the contactor g closes, in starting the motor E, it makes up acircuit for the magnet 26 of a relay I, which circuit is normally openat the push button marked Start". This circuit extends from supply wireL through conductor 2'! and the start push button to magnet 26, thencethrough conductor 28 to a contact 29. An insulated contact I I on thecontactor arm I l engages and electrically connects this stationarycontact with a contact 30 which is connected by wire 3i to conductor 2|which leads through the stop push button switch to the supply wire L'.

The relay circuit thus made up may be completed by momentarilydepressing the start" push button. The relay I controls the operation ofan automatic motor starter N comprising a main contactor n and anauxiliary contactor n, and the starter in turn, controls the operationof the motor D which circulates air around the condensing coil 2.

Closure of the start push button will not eiIect any result, except whenthe contactors of the starter G-are closed and the fan motor E isrunning, because the circuit of the relay I is always open at thecontactor y when the latter is in its open position. When this pushbutton switch is closed after the motor E has been started, the relay Ioperates to complete a holding circuit for its magnet in shunt to thestart" push button, this shunt extending from supply wire L throughconductor 32 to a contact 33 which is connected to a contact 34 by aninsulated contact 35 on the movable member of the relay, and a conductor36 connects the contact 34 with the circuit of the relay magnet betweenthe coil of the latter and the start push button.

A conductor 31 leads from the supply wire L to a stationary contact 38of the relay I and when the relay is'closed,.an insulated contact 39connects the contact 38 with a contact 40 and makes up a circuit throughthe thermostat T, as follows: from the supply wire L through conductor31 and relay contacts 38, 39, and 40 to conductor 4!, thence throughcoil of starter magnet 42, thence by conductor 43 to tripping switchmembers 44-45, thence by conductor 46 to an over-pressure switch 41,thence by conductor 48 to under-pressure switch 49, thence by conductor50 to thermostat switch T and thence to supply wire L.

If the thermostat switch happens to be open,

because the air in the room is above the predetermined temperature, noresult will follow the making up of the circuit just traced by theclosure of the relay I; but if the thermostat switch is closed at thistime, because of lower room temperature, the magnet 42 will be energizedand the contactors of the starter N will close in succession, completingthe circuits of the motor D and making up circuits for the devices whichcontrol the starting of the gas engine.

The starter N. is the same as the starter G, except that the magnet 20of the latter has a holding circuit which keeps the main contactorclosed until the stop push button switch is opened, while thecorresponding magnet 42 of the starter N has no holding circuit and isonly energized while its circuit is complete through the thermostatswitch, the relay I and the -switches 44-45, 41 and 48. The circuits ofthe motor D are the same as the circuits of the fan motor E. Thus thearmature circuit of the' motor D extends from supply wire L throughconductor 5| to arm 52 of main contactor n, thence through conductor 58to the series coil 54 of contactor n, thence by conductor 55 throughstarting resistance 58 to the series coil 51 of the motor, thence to thearmature of the motor and to supply wire L, as shown. The shunt fieldcircuit extends from conductor 53 through conductor 58 to the shuntfield winding 58 and thence to the supply wire L. The conductor 58connects the arm 52 of the main contactor to the arm 60 of the auxiliarycontactor.

When the main contactor closes, it completes circults through the seriesmagnet 54 and the shunt magnet BI oi the auxiliary contactorsimultaneously, the circuit of the latter magnet extending from supplywire L and conductor 5| through conductor 62 to the magnet 6|,thence toconductor M and contacts of relay I and conductor 31 to supply wire L.When the auxiliary contactor n closes, it forms a shunt around thestarting resistance 55 through conductor 58 and the motor D thenoperates at full speed.

The contactors of the starter N, which close when the thermostatswitchcloses, serve as relays, cooperating with the relay I, to make upcircuits for the various engine controlling devices. Thus, the auxiliarycontactor n, in closing, connects a trunk line conductor 85 throughconductor 68 and relay I to conductor 81 which is connected to thesupply wire L'. The main contactor n, in closing, connects one terminalof the coil of relay F to supply wire L through conductors 81 and 5I,and the other terminal of the coil is permanently connected to theconductor 85 by conductor 68. Hence, when the starter N operates, therelay F is energized and operates to close the ignition circuit 69 ofthe gas engine;

The motor 10 of the timing mechanism J is also energized upon theclosure of the contactors of the starter N. The circuit of this motorextends from the trunk line conductor 85 through conductor II to themotor and thence through conductors 12 and 13 to a normally closed cenbyconductor I1 to the trunk line conductor and the other terminal of thecoil is connected by conductor 18 to the stationary contact 88 on thetiming mechanism. As hereinafter explained more in detail, the timingmechanism connects this rela'y. through conductor I8 and the governorswitch to the side L of the supply circuit, and the relay then closesthe circuit 50 of the starting motor C which cranks the engine duringthe period while the relay is closed.

The magnet H has one terminal connected by conductor 8| to the trunkline conductor 05 and the other terminal is connected by wire 82 tostationary terminal 8i of the timing mechanism. During the crankingperiod, the timing mechanism closes the circuit of this magnet throughthe centrifugally operated switch, as hereinafter described. When themagnet is energized, it operates to close a choke valve 84 on theengine,

to cause enrichment of the explosive mixture.

When the engine starts, the circuits through the devices M and H, aswell as through the motor 10, will be broken by the governor switch.

The timing device J, comprises the small motor 10 to which is geared bysuitable reduction gearing a slow moving cam shaft 85 on which aremounted six segmental cams 88, 81, 88, 89, 90, and SI, of insulatingmaterial. The cams are adapted to bear against rollers on the rear endsof switch arms 86 to 9|, respectively, and these arms are spring-pressedtoward stationary contacts 86' to 8I respectively. As shown in thediagram, the switch arms are arranged in electrically connected pairs.The pair BB -81, connected by a conductor 94. controls a relay 0; thepair 88 -89, connected by a conductor 95, controls the circuit throughthe starter relay M, and the pair 90*8I, connected by a conductor 86,controls the circuit through the magnet H which operates the chokevalve.

The cams. 86 and 81 are set so that after a short period during therevolution of the cam shaft both of the switch arms 86 and 81 will beclosed on their respective contacts 86 and 81 When these switches areboth closed, a circuit from conductor 85, which is then connected to theside L of the supply circuit, through conductor 81 to the coil 88,thence by conductor 89 -to contact 81*, thence through arm 01, connector94, arm 86*, contact 86 and conductor I00 to the conductor I3 whichleads through the governor switch to the side L of the supply circuit.The relay arm MI, in closing, will bridge contacts I02 and I08 and itwill establish a holding circuit from contact I02 through arm IOI,conductor I04, resistance I 05, coil 98 andconductor 91 to conductor 55.The magnet will hold the arm IOI in closed position after the circuitinitially established through the magnet by the switch arms Ni -81 isbroken. The closure of the relay will also make up a circut fromconductor 18 through contact I08 and conductors I05 and I0! to thestationary contacts 88 and 90 and it will complete a circuit through theclutch magnet I 08 of the tripping device K as follows: from the side Lof the supply circuit through conductors 15 and 18 to contact I02,thence through relay arm IM to conductor I04, thence through coil ofmagnet I08 and conductor IIO to the trunk line conductor 65 which isconnected, at the time, through the interlocks described, to the side Lof the supply circuit. This magnet immediately .attracts its armatureIII, against the action of a spring-pressed pin H2, and the upper end ofsteel rack rod H3, which is slidingly mounted on the armature, is drawnagainst the flanged end I I4 of the magnet frame I I4, as shown indotted lines, in position to be engaged by a tooth I I5 on a sleeve H8which is secured to the end of the shaft 85. This rack rod operates toopen the switch 44-45 if the engine does not start after a predeterminednumber of revolutions of the shaft 85. The details of the trippingdevice are shown in my original application'before mentioned.

When the motor 18 starts, by reason of closure of the thermostat switch,and after the cams 86 and Bl have caused the closure of the circuitthrough the magnet of relay 0, the cams 88 and 89 cause the connectedswitch arms 88 and 89- to engage the contacts 88 and 89", respectively,and complete a circuit through the magnet of relay M which operates toclose the circuit 86 of the starting motor C, and the engine is crankedby the latter motor. Contact 89' is, at this time, connected to the sideL of the supply circuit through the coil of the magnet of relay M andconductor 65, and the contact 88 is connected to the supply wire Lthrough relay 0, conductor 13, centrifugal switch 14 and conductor 15.

The cranking period of the engine depends upon the setting of the cams88 and 89. If the engine is warm, it may start as soon as the crankingoperation is commenced, and as the ignition circuit is closed by therelay F, if the engine starts aftera few moments, the centrifugalgovernor 16 will open the switch I4 and interrupt the circuit to themotor 10 and also the holdin circuit of the relay 0, and thus thecurrent to the timing mechanism will be completely cut oil.

If the engine does not start within a predetermined time after thecranking operation commences, the choke valve of the engine will beclosed, to enrich the mixture, while the cranking continues. The magnetH which controls the choke valve is in a circuit which is controlled bythe connected arms 90 and 9|. While these arms are both in engagementwith their respective contacts, the magnet H will be energized and thechoke valve will be closed. The circuit for the magnet extends fromconductor 65 through conductors BI and 82 and the magnet coil to contact9 l thence through arms 9| and 98* to contact 90 thence throughconductors I01 and I06 and relay to the conductor 13. If the enginestarts while the choke valve is closed, the centrifugal governor switchwill break the circuit through wire 13 and the circuits through motor10, starter relay M and choke valve magnet H and clutch magnet Hi8 willbe interrupted.

If the engine does not start after the choking operation, the circuitthrough wire 13 will not be broken and the operations of cranking,without choking, and then with choking will be repeated during eachsucceeding revolution of the shaft 85 until the engine starts, or untilthe tripping device K operates to break the circuit in which areincluded the several safety switches, the thermostat and the magnet 42.'The interruption of this circuit renders all of the engine controllingdevices inoperative until the continuity of the circuit is restored bythe manual resetting of the tripping device.

The tripping device can be arranged to open the switch 44-45 after anydesired number of revolutions of the cam shaft, by providing a suitablenumber of teeth on the rack rod. If the engine does not start after alimited number of choking and cranking operations, it is desirable tothrow the engine controlling devices out of action as the failure tostart may be due to lack of fuel or other causes requiring personalattention. Therefore, after four or five revolutions of the crank shaft,the tripping device will operate to separate the contacts 44 and 45 andas these are in circuit with the magnet 42 of the starter N, thecontactors of the starter will open the circults of the devices whichcontrol the starting and operation of the gas engine. Before the enginecan be started again, the switch 44-45 must be reset by hand.

For testing the engine controlling system while the thermostat switch isopen, a switch I28 is shown for shunting the thermostat switch andsimilar shunting switches may be arranged around the pressure controlledswitches 41 and 49.

The operation of the system will be clear from the foregoing, withoutfurther extended description. When the cooling system is to be used, thefan motor E is started by depressing the fan push button. This motoroperates to circulate the air of the room through the refrigerating coil5. It is essential to have this motor in operation at all times whilethe compressor is in operation and it may be desirable to have itoperate to circulate air in the room even when the cooling system is notin use. Therefore, the circult arrangements are such that the compressorcannot be started until after the motor E has been started, and whenthis motor is stopped, the gas engine will also stop.

After the fan motor E has been started, the

-start push button, when depressed, will cause the relay I to make upcircuits for the starter N. The starter N is controlled by a circuit.which includes the thermostat switch, trip switch 4445, pressurecontrolled switches 41 and 49 and also the magnet 42 which actuates themain contactor of the starter N. When the thermostat switch closes, thisstarter causes motor D to circulate air or other cooling fluid aroundthe condensing coil 2 and the closure of the starter contactors make upthe circuits for the various engine controlling devices. first closedand the timing mechanism causes the starter motor to crank the engine,and during a part of the cranking operation the choke valve is closed.Also the clutch magnet which moves the rack rodinto operative engagementwith the timing shaft is energized. If the engine starts after one or apredetermined number of cranking and choking operations, the enginecontrolled switch I4 opens the circuit to the timing mechanism and thecircuits which control the starter motor and the magnet for operatingthe choke valve and the clutch magnet are opened, while the ignitioncircuit, controlled by a relay connected to a circuit independent of theengine controlled switch, remains closed. If the engine does not startafter a predetermined number of cranking and choking operations, thetripping device operates the circuit breaker and the magnet controllingthe starter N is de-energized and the opening of the starter contactorscuts off the motor D and the various engine controlling devices.

When it is desired to discontinue the use of the apparatus for a time,the stop push button is depressed and this de-energizes the starter "3causing the fan motor E to stop. When the com tactors of the starter Gopen, the interlocking connection to the magnet of the relay I isbroken, and when this relay opens, the interlocking connections to thestarter N are broken, and when the contactors of the latter starteropen, the motor D stops and the circuits which control the enginestarting device are also interrupted.

What I claim is:

1. In an air cooling system, a compressor and driving means for thesame, a condensing coil The ignition circuit is' and a refrigeratingcoil connected to the compressor, an electric fan motor for circulatingair around the refrigerating coil, a starter for said motor, a normallyopen manually operable switch controllingthe operation of said starter,an electric motor for circulating cooling fluid around the condensingcoil, a starter for the latter motor and means controlled thereby foroperating the compressor, and interlocking connections between saidstarters whereby the first mentioned starter must be closed before thesecond mentioned starter can be closed.

2. In an air cooling system, a compressor and driving means for thesame, a condensing coil and a refrigerating coil connected to thecompressor, an electric fan motor for circulating air around therefrigerating coil, a starter for said motor, a normally open manuallyoperable switch controlling the operation of said starter, an electricmotor for circulating cooling fluid around the condensing coil, astarter for the latter motor and means controlled thereby for operatingthe compressor, interlocking connections between said starters wherebythe first mentioned starter must be closed before the second mentionedstarter can be closed, and a normally open manually operable switch forinitiating the closure of the second mentioned starter.

3. In an air cooling system, a compressor and driving means for thesame, a condensing coil and a refrigerating coil connected to thecompressor, an electric fan motor for circulating air around therefrigerating coil, a starter for said fan motor, a circuit controllingthe operation of said starter including a normally open manuallyoperable switch, an electric motor for circulating cooling fluidaroundthe condensing coil, a starter for the latter motor, a relay controllingthe operation of the last mentioned starter, a circuit for said relaycontrolled by said first mentioned starter and including a normally openmanually operable switch, and means, controlled by the starterfor themotor which circulates fluid around the condensing 'coil, for operatingthe compressor. 7

4. In an air cooling system, a compressor and pressor, an electric motorfor circulating cooling Q fluid around the condensing coil, a starterfor said motor, means controlled by said starter for operating thecompressor, a normally open switch controlling the operation of saidstarter, an elec-' tric' fan motor for circulating air around therefrigerating coil, and a starter for the latter motor controlling theoperation of said switch.

5. In an air cooling system, a compressor, a condensing coil and arefrigerating coil connected to the compressor, an electric motor forcirculating cooling fluid around the condensing coil, a starter for saidmotor, a normally open switch controlling the operation of said starter,driving means controlled by said starter for operating the compressor,an electric ianmotor for circulating air around the refrigeratingcoil, acircuit for the fan motor, switch mechanism for closing and opening saidlatter circuit to start and stop said fan motor at will, and connectionswhereby the aforesaid starter may be made operative only while thecircuit of the fan motor is closed.

, 6.v In an air cooling system a compressor and a driving motor for thesame, a condensing coil and a refrigerating coil connected to thecompressor, an electric fan motor for circulating air around therefrigerating coil, a circuit for the fan motor, switch mechanism forclosing and opening said circuit to start and stop said fan motor atwill, starting means for said driving motor and connections whereby saidlatter means may be made effective only while the circuit of the fanmotor is closed.

7. In an air cooling system, a compressor, driv ing means for the same,a condensing coil and a refrigerating coil connected to the compressor,electrically operated means for starting said driving means, an electricfan motor for circulating air around the refrigerating coil, switchmechanism for closing the circuit of said fan motor, and meanscontrolled by said switch mechanism for making said starting meansoperative only while the circuit of the fan motor is closed.

JOSEPH F. FRESE.

